1. Field of the Invention
This invention relates to computer operating system software and more particularly to a method and system for communicating between computer application programs and various computer text services.
2. Description of the Background Art
An on-going problem in designing computers for use worldwide is adapting the standard QWERTY-type keyboard to handle the large number of characters found in the various written languages. For instance, written Chinese has no alphabet, instead it consists of approximately 50,000 characters. The Chinese writing system is logographic, meaning that each character stands for a word or part of a word. Popular Chinese writings including newspapers and novels use a sub-set of the total character set consisting of approximately 4,000 of the more commonly used graphs. Chinese text input on a computer requires a conversion using a series of keyboard keystrokes, for example from Pinyin (Roman) or Zhuyinfuhao (phonetic), to logographic Hanzi Chinese characters. Many other methods of generating Hanzi using a keyboard input are also possible.
The Japanese character set is borrowed from the Chinese system of writing. Characters from the Chinese system were simplified and codified into syllabaries, or tables of syllables, in written symbols cared kana. The two syllabaries in use today include the more commonly used rounded form known as hiragana and the less frequently used, square-shaped katakana. Modern Japanese writing, called kanji, is a combination of Chinese characters and kana. The official kanji character set has several thousand characters, although many more thousands of characters are in common use.
Similarly, Korean text input requires conversion from Jamo (phonetic) to non-ideographic Hangul, which consists of complex clusters of Jamo. The general approach to accessing the many letters of these character-based written language sets is to use a series of key strokes to either phonetically or symbolically address the desired character. The Japanese kanji equivalent of TOKYO, for instance, is the phonetic sequential characters TOU and KYOU.
To assist users of character-based text processing software, software developers have produced Front-End Processors (FEP's), which convert the sequential keyboard entries of the user to an appropriate letter of the target character set. These FEP's are also often referred to as "input methods". The front-end processors in the past have been very inflexible. Each application has had a specific FEP associated with it, and the user has had little choice as to which FEP was available. Users had little or no choice between using a phonetic-based FEP or a stroke-based FEP for a given application. This inflexibility between input methods is a particular problem when attempting to generate a document having multiple language translations, such as multi-national user's manual.
In addition to written language front-end processors, application programs take advantage of numerous other text services modules which augment and facilitate the capabilities of the application. Typical additional text services include spelling checkers, hyphenation checkers, grammar checkers, dictionary lookup services, thesauruses, syntax checkers and equation processors.
What is needed is a computer operating system text services manager which operates as an interface between a given application and a selection of text services, enabling the user to select from among and switch between various text services, without regard for the specific protocol requirements of the application.